Incremental modular home gateway

ABSTRACT

The invention concerns a communication device including several external data sources, at least a local area network connecting peripherals, means enabling to establish connections between the local area network and the external data sources, means for controlling the incoming data from the external sources and for sending them to the local area network in order to reduce the bandwidth occupation on the local area network. The device also includes means for updating signalization tables included in the incoming data and means for inserting the modified signalization tables in the transport stream sent to the local area network. It is applicable to IEEE 1394 networks.

This application claims the benefit, under 35 U.S.C. §365 ofInternational Application PCT/EP03/50216, filed Jun. 5, 2003, which waspublished in accordance with PCT Article 21(2) on Dec. 24, 2003 inEnglish and which claims the benefit of European patent application No.02364030.3, filed Jun. 13, 2002.

The invention concerns a communication device and a communicationmethod.

BACKGROUND OF THE INVENTION

The invention can be applied for example in the field of home networks.

Typically, a home network allows communication, connection,interoperability between video equipments for personal or recorded videodisplaying, video games, . . . but mainly it should give to the user theopportunity to communicate easily with the external world.

Video programs, images, music, text pages, information data can beaccessed from numerous sources provided by different heterogeneous meansof transmission.

For example, television can be broadcasted from satellite, terrestrial,cable, LMDS (Broadcast Network) or delivered by Internet (BroadbandNetwork). That is also true for music or web pages. There is no limit inmixing technologies.

A first approach to connect and adapt the home network to the outsideworld is to use a residential gateway that has numerous means ofreception, a bridge that translates the transport protocol of theincoming data to the protocol supported by the home network.

A solution, commonly proposed, is to provide a box with slots (commonlyPCI slots) in which the proper daughter boards are inserted according tothe accesses requested by the user.

Such a solution is proposed in the patent application WO 00/11840 filedin the name of Mitsubishi on Aug. 12, 1999 entitled “home gateway”.

This solution presents a lot of drawbacks that are commonly not admittedin consumer products:

-   -   In consumer products, opening the box is performed by servicing        people only. Allowing consumer to add boards by himself is not        admitted.    -   The basic platform that will receive add-on board(s) has        features that will never be used, but they must be paid by the        consumer, making the product less competitive for low-end        configuration.    -   More complicated the product is, more expensive it is.        Connectors, oversize power supply, large case . . . don't        characterize low cost product.    -   An open system can be tampered more easily, paving the way to        the hackers for unauthorized acts.

Patent applications WO 99/57839 entitled “method and apparatus for userand device command and control in a network” filed on May 7, 1999 and WO01/13374 entitled “device communication and control in a home networkconnected to an external network” filed on Aug. 17, 2000, both filed inthe name of Samsung, describe a system interconnecting several externalsources to a local area network. Each module provides a connection withan external data source. However, such modules do not modify theincoming stream in order to enable the cohabitation of several streamson the local area network and in particular do not adapt the incomingstreams data rate to the limited bandwidth of a local area network.

BRIEF SUMMARY OF THE INVENTION

The invention proposes a communication device comprising

-   -   several external data sources,    -   at least a local area network connecting peripherals,    -   means enabling to establish connections between the local area        network and the external data sources,    -   means for controlling the incoming data from the external        sources and sending them to the local area network in order to        reduce the bandwidth occupation on the local area network.

According to the invention, the device comprises:

-   -   means for updating signalization tables comprised in the        incoming data,    -   means for inserting the modified signalization tables in the        stream sent to the local area network.

Such a device controls the incoming data and thus, when the local areanetwork is connected to many external sources, the invention isparticularly suitable as it improves the simultaneous transfers of datafrom the different external sources.

According to a preferred embodiment, the communication device isintended to establish one connection with an external source uponrequest of peripherals of the local area network.

The connection with an external source is then made when requested, thiscan enable to save bandwidth on the local area network. Moreover, thanksto the means for controlling the incoming data, the bandwidth occupationis optimized for serving as many as possible requests from theperipherals.

According to a preferred embodiment, the communication device comprisesfiltering means intended to remove some data coming from the externalsources to create a single program transport stream or a partialmultiple program transport stream for the local area network from themultiple program transport stream selected from the external source.

A way to reduce the bandwidth is to remove the unnecessary informationfrom the incoming data stream. When the incoming data stream comprisestransport streams composed of several programs, some of the programs maynot be requested by peripherals on the local area network. Thus a way toreduce the bandwidth is to remove the programs having packet identifiersnot requested by the peripherals.

According to a preferred embodiment, the communication device comprises

-   -   means for updating signalization tables comprised in the        incoming data,    -   means for inserting the modified signalization tables in the        stream sent to the local area network.

When the incoming data is composed of several audio and video streams,the selection of one or more audio or video programs implies also themodification of the tables describing the content of the stream. Thetables are modified and then reinserted in the modified stream.

According to a preferred embodiment, the filtering means are intended toremove packets containing non-requested packet identifiers from themultiple transport streams to create single transport streams.

According to a preferred embodiment, the communication device has meansto guarantee a copy protection of the data coming from the externalsource.

Content protection is a key concern in providing audio video data tosubscribers.

Some audio video digital programs, music, data are free, some others arein the copyright. These ones are mostly scrambled.

When a customer has paid rights, he can display and record the analogpictures.

In a network, every data of any type can be stored, modified,transmitted, duplicated without significant distortion thanks to thepowerful features of the digital equipments that are interconnected.

Royalties must me preserved on one hand and, in the other hand, somecopy permission could be granted to the customer.

For the customer, copy permission could be as simple as an instantdisplay or as permissible as a full ownership. Access control level isgranted by the owner of the material and the rights are managed by theaccess control of the gateway module.

Thanks to the access control from the gateway module, all the data inthe copyright that are available in the home network have been given theaccess by the copy protection system.

According to a preferred embodiment, the local area network is compliantwith IEEE-1394 protocol.

According to a preferred embodiment, the communication device isintended to generate a data stream on the local area network compliantwith DVB or DSS standard.

The invention also concerns a system comprising:

-   -   Several external data sources,    -   At least a local area network connecting peripherals,    -   A gateway enabling to establish connections between the local        area network and the external data sources, the gateway        -   being distributed among some peripherals, called gateway            modules, and        -   comprising means for managing the introduction or the            withdrawal of new gateways modules,    -   Each gateway module comprising means enabling it to establish a        complete connection between the local area network and an        external source, the other gateway modules having established or        not a connection with an external source,    -   Characterized in that each gateway module is a communication        device according to claims 1 to 9.

When the home network is compliant with the IEEE-1394 network, an otherfact is often ignored by IEEE-1394 gateway designers:

-   -   The number of simultaneous accesses to the gateway is limited by        the number of isochronous channels that can be opened, mainly        due to hardware limitations. That feature depends on the        IEEE1394 bus chipset. So, even many slots are populated, only        one, two or, in any case, a finite number of them would be used        simultaneously.

A modular gateway as proposed can enable the access to severalisochronous channels as each module has its own IEEE-1394 interface andthe controlling means enable the cohabitation of the differentisochronous channels by sharing the bandwidth among the differentgateway modules.

The invention also concerns a communication method between severalexternal data sources and a local area network, said local area networkconnecting peripherals, comprising the step of:

-   -   enabling the set-up of connections between the local area        network and the external data sources,        characterized in that it further comprises the step of:    -   controlling the incoming data from the external sources and        sending them to the local area network in order to reduce the        bandwidth occupation on the local area network,    -   said method being preferably intended to be implemented in a        device according to any embodiment of the invention.

The invention also concerns a computer program product comprisingprogram instructions for executing the steps of the method for creatingsemantic browsing options according to the invention, when said programis loaded on a computer.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the invention will appear in the followingdescription of exemplary embodiments made with reference to the attacheddrawing where:

FIG. 1 represents a communication device according to an embodiment ofthe invention,

FIG. 2 represents an example of a stream filtering process,

FIG. 3 represents a system implementing gateway modules according to anembodiment of the invention,

FIG. 4 represents the layers and the protocol stacks that control adevice according to a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The preferred embodiment illustrated by the different figures is basedon a local area network compliant with the IEEE-1394 standard and theincoming stream is compliant with MPEG-2 standard.

On FIG. 1, the device 1 comprises a receiver/demodulator module 2connected to an external network 17.

The external network 17 can be a broadcast network, such as a satellite,a terrestrial or a cable network. The receiver demodulator module 2comprises radio frequency circuits, a QPSK (standing for “QuaternaryPhase Shift Keying”, a COFDM (standing for “Coded Orthogonal FrequencyDivision Multiplexing”) or QAM (standing for “Quadrature AmplitudeModulation”) demodulator according to the type of chosen front end.

The external network can also be a broadband network such as an ADSL(standing for “Asymmetric Digital Subscriber Line”) network. It givesthe means of communication according to the IP protocol for accessingthe broadband network.

The receiver demodulator 2 is connected to a signal processor 3.

The signal processor 3 comprises at least a stream filtering module 16,a tables updating module 15, a content protection module 14 and an IPbridging module 18.

The filtering module is in charge of controlling the incoming data fromthe external network 17, in order to save bandwidth on the IEEE-1394network.

Saving bandwidth on the local area network is particularly importantwhen several communication devices 1 are connected to the local areanetwork. Each of the device being for instance connected to a differentexternal network, enabling the end user to access several externalnetworks such as ADSL, cable, satellite, . . . .

One limit in connecting a large number of devices 1 is the bandwidth ofthe IEEE-1394 network at a given time. When the client terminal, calledalso peripheral, is requiring a new stream, the local area network canafford the extra load or not.

The interoperability middleware takes care about the status of the homenetwork and assists the user to optimize the network via the UserInterface.

Very often, only a program from a multiple program stream is requestedso the required bandwidth is reduced; if the incoming stream iscompliant with MPEG-2, the stream can be reduced from 30 Mb/s (the wholemultiple program) to 4 Mb/s. So, each time one program is requested, thestream is sorted to make a SPTS (Single Program Transport Stream) fromthe MPTS (Multiple Program Transport Stream).

The Program Tables are modified in relationship with the new content ofthe stream.

The SPTS is created by removing unused PIDs (standing for “PacketIdentifiers”) from the MPTS without modifying the PTS/DTS (standing for“Presentation Time Stamp/Decode Time Stamp”), then the packets occupythe same temporal location making a stream with holes.

The resultant transport stream is DVB (standing for “Digital VideoBroadcast”) or DSS (standing for “Digital Satellite System”) compliantso it is directly sent to the IEEE-1394 bus chipset that is designed forbroadcasting isochronous DVB or DSS streams on the home network.

FIG. 2, described later, represents an example of the filtered stream

The signal processor 3 comprises also a module 15 in charge of updatingthe tables of the incoming stream towards the filtered stream.

The transport stream tables of information describe the content of thestream. They are transmitted inside packets with a known packetidentifier (PID).

These packets of data are sorted and temporary stored in a memory of thesignal processor 3, such as a FIFO (standing for “First-In First-Out”)memory.

When a predetermined number of packets are stored, they are transferredto the DRAM (standing for “Dynamic Random Access Memory”) 12. The tablesare then analyzed by a processor 6, modified and updated. Then, they aretransferred back to the memory of the signal processor 3. As soon as apacket is ready, it is inserted into the stream in place of a hole inthe stream. The holes are created by the filtering module when somepackets containing non requested PIDs are removed from the MPTS stream.

The signal processor 3 comprises also an IP (standing for “InternetProtocol”) bridging module 18.

IP bridging is performed according to the RFC 2374 December 1999 by P.Johansson that specifies how to use the IEEE Std-1394-1995 for a highperformance serial bus, for the transport of Internet Protocol version 4(Ipv4) datagrams; it defines the necessary methods, data structures andcodes for that purpose. These include not only packet formats andencapsulation methods for datagrams, but also an Address ResolutionProtocol (1394 ARP) and a Multicast Channel Allocation Protocol (MCAP).Both 1394 ARP and MCAP are specific to Serial bus; the latter permitsmanagement of serial bus resources when used by IP multicast groups.

The module 3 comprises also a content protection module 14.

As explained earlier, the copy protection system enables the copyrightprotection of the programs and also enables, if allowed, the copypermission to the end user.

Such a content protection module is thus important in the field of audiovideo content where copy protection is a key concern.

In a preferred embodiment, the used copy protection system is associatedwith a smart card reader 11. The smart card reader enables the user tobe identified and informs also the device 1 of the rights of the user.

The signal processor module is connected to an IEEE-1394 port 13composed of a link layer and of a physical layer. It is a standardinterface to an IEEE-1394 network. Two IEEE-1394 ports are connected toenable the chaining of peripherals.

A flash memory 7 and a read only memory (ROM) 8 are connected to theIEEE-1394 port, to a processor 6 and to the signal processor 3.

The flash memory 7 and the Rom memory 8 are used by the processor 6 tostore the code instructions. A DRAM (standing for “Dynamic Random AccessMemory”) 12 is also connected to the processor.

Device 1 also comprises a power supply unit 9, and a clock module 10 incharge of providing clocks to the different modules of device 1.

An I2C (standing for “Inter-Integrated Circuit”) interface is alsoconnected to the receiver demodulator 2 and to the processor 6. Theregisters of the tuner and the demodulator are programmed through theserial bus interface I2C.

A phone modem 5, that performs the access to the external network,allows the connection with the broadcaster for interactive TV or theconnection to a server for Internet services.

In the cable version, not represented, a modulator can be added toprovide a return channel for data returned to a server by using thecable as a bi-directional link.

A firmware 19 is also running under the control of the processor andwill be described with the help of FIG. 4.

FIG. 2 represents an embodiment of a filtered stream.

The incoming stream is, in a preferred embodiment, a Multiple ProgramTransport Stream (MPTS) compliant with MPEG-2 standard.

Such a stream includes multiple programs. Among these programs, some ofthem may not be required by the peripherals located on the IEEE-1394network. So the filtering module 16 of the signal processor 3 is incharge of removing the data packets, which are not required by theperipherals.

The MPTS stream comprises also the information tables represented by theSI (standing for “System Information”) packets. SI packets are extractedfrom the incoming MPTS stream and modified according to the newlycreated stream, called pseudo SPTS stream, which contains only the datapackets, which are requested by the peripherals, the modified SI packetsand holes instead of the removed packets.

FIG. 3 represents a system including several devices 1 according to apreferred embodiment of the invention.

A house 32 comprising a home network connected to external sources, 28,29, 30, 31, is represented.

The home network comprises an IEEE-1394 network connecting severalperipherals such as a home server 20, a primary display 22, a camcorder23, a digital recorder 21, a personal computer 24, a secondary display26 and two wireless transmission modules 25 and 27.

Four devices A, B, C, D, also called gateway modules, are each connectedto an external source.

Modules A and B are respectively connected to satellite antennas 28 and29. Module C is connected to a terrestrial TV antenna 30, module D isconnected to an ADSL network 31.

The gateway modules are, in a preferred embodiment, clustered in anattic or a cellar of the house. They are chained and only one opticalfiber links the cluster to the rest of the network. Such an opticalfiber enables to have a relatively long haul transmission or linkbetween the cluster of gateways and the rest of the network. This can beof interest for a home installation purpose.

Such a system enables the connection to several external sources and thenumber of connections is not limited by the bandwidth of the network aseach of the gateway modules has controlling means enabling it tooptimize the amount of data sent to the local area network. Moreover,one great advantage of having each gateway connected to an externalsource is that each of the gateway module has an IEEE-1394 port and thusa sufficient number of isochronous channels can be handledsimultaneously. The gateway is thus distributed, fully scalable, givingthe end user the best freedom in building its own network. The globalgateway function is the sum of small hardware devices controlled byclients in a home network. Clients can be the displays 22 or 26, thehome server 20, the digital recorder 21 or the analog camcorder 23.

FIG. 4 gives an illustration of the layers and the protocol stackscontrolling the device 1.

The firmware stack is running under control of a real time operatingsystem.

At low level, the hardware adaptation layers are composed of severalinterfaces according to the external sources that are connected.

The hardware adaptation layers make the interface between the receiversand the upper protocol stacks.

The hardware interface in use is depending on the type of the gatewaymodule: it depends on the external source the gateway module isconnected to.

A module 37 controls the access to the IEEE-1394 local area network.

A module 35 controls the access to the broadcast network and a module 35controls the access to the broadband network.

The upper layer is a kernel core in charge of the protocols supported bythe gateway modules. The kernel core comprises:

-   -   a module 39 for managing the IEEE-1394 link,    -   a module 38 dealing with the DVB, DSS, ATSC (standing for        “Advanced Television System Committee”) transport streams. The        protocol stack is compliant with the standardized        specifications.    -   a module 34 supporting main transport protocols like TCP        (standing for “Transmission Control Protocol”), UDP (standing        for “User Datagram Protocol”), RTP (standing for “Real time        Transport Protocol”).

The upper layer called “user's libraries core” supports a proprietaryinteroperability protocol. In another embodiment HAVI (standing for“Home Audio Video interoperability”) or other protocol can also beimplemented.

An API (standing for “Application Programming Interface”) is deliveredfor allowing an easy implementation of the user application. The userapplication includes the remote control of the gateway module, dataprocessing . . .

1. A system comprising: external data sources, a local area networkconnecting peripherals, a gateway for establishing connections betweenthe local area network and the external data sources, the gateway beingscalable such that the gateway is distributed among some peripheralscalled gateway modules, each gateway module connected to at least oneexternal data source, the gateway modules being chained together, andeach gateway module managing introduction or withdrawal of new gatewaymodules, each gateway module comprising means to establish the completeconnection between the local area network and the external data sourceindependently of whether other gateway modules have established aconnection with an external source, wherein each gateway module handlesa plurality of isochronous channels on the local area network, whereinadding new gateway modules increases the number of isochronous channelson the local area network, and wherein each gateway module has means forcontrolling incoming data from a multiple program transport streamreceived from one external data source according to one request of aperipheral on the local area network and for sending the incoming datareceived from the one external data source to the local area network inorder to reduce bandwidth occupation on the local area network.
 2. Thesystem according to claim 1, wherein the gateway module comprises: meansfor updating signalization tables comprised of the incoming data, andmeans for inserting the modified signalization tables in the transportstream sent to the local area network.
 3. The system according to claim1, wherein the filtering means removes packets containing non-requestedpacket identifiers from the multiple program transport streams to createthe single program transport stream.
 4. The system according to claim 1,wherein the gateway module has means to guarantee a copy protection ofthe incoming data coming from the external source.
 5. The systemaccording to claim 1, wherein the local area network is compliant withIEEE-1394 protocol.
 6. The system according to claim 1, wherein thegateway module generates a data stream on the local area networkcompliant with DVB or DSS standard.
 7. A system according to claim 1,wherein the means for controlling incoming data comprises filteringmeans for removing some of the incoming data to create a single programtransport stream or a partial multiple transport stream for the localarea network from the multiple program transport stream, wherein packetsof the single program transport stream or the partial multiple transportstream occupy a same temporal location as corresponding packets in themultiple program transport stream.